Sacred Indian texts (from the Sanskrit word tan meaning "to span" or "to loom". The Tantras cover a unique aspect of literary and meditative thinking in India that ran against the dominant cultural patterns of the time. The Buddhist Tantras which were written between 500 and 800 CE. The Hindu Tantras came later, between 900 and 1400 CE. They were meant to instruct the devout on how to use mental and physical techniques to escape the eternal cycle of birth-death-rebirth (see karma, transmigration and reincarnation). Unlike the conservative ascetics practicing Yoga, the Tantrics learned to harness sensual powers to pursue freedom and wisdom.

The religion, Tantrism, based on the tantras, is founded on a dual manifestation of the supreme being, that of male and female principles. In Hindu Tantrism, the male principle (Siva) is passive and represents perfect knowledge. The female principle (Sakti) is dynamic and active, representing energy and motion. In the Buddhist version, sometimes called Vajrayana (which means "the vehicle of the thunderbolt"!), the male principle (Prajna) represents perfect wisdom.

This duality is often represented with sexual imagery, where male and female participants prolong activity without orgasmic release. It is believed that the power of retention can bestow enormous psychic control to the participants, eventually leading to their freedom from the birth-death-rebirth cycle. Additionally, Tantrics ingest marijuana and alcohol, and consume meat, fish an various aphrodisiacs. Not surprisingly, most Hindus regard Tantrics with some suspicion. Although Tantrism is not a large part of Hinduism in general, it is integral to Vajrayana Buddhism.